Ground anchors

ABSTRACT

A ground anchor which is self-righting and self-engaging under the action of the anchor rope, comprises a shank with an oblique fluke plate at one end and a self-righting device at the other. The self-righting device has a plurality of arms fixed to and projecting laterally from the shank, arranged such that by pulling on the anchor rope when the anchor is disorientated at least one of the arms engages the ground and reacts with the ground to correct the orientation of the anchor for correct ground engagement of the fluke plate. The self-righting device can include three arms, one arm being perpendicular to the other two arms which are in line, on either side of the shank.

UnitedStates Patent [191 Vinyc omb Aug. 13, 1974 GROUND ANCHORS [75] Inventor: William Anthony Vinycomb,

Lymington, England [22] Filed: Jan. 26, 1973 [21] Appl. No.: 326,688

[30] Foreign Application Priority Data 2,103,477 12/1937 Lucking ..ll4/207 2,490,378 12/1949 Moult 52/155 X 3,305,984 2/1967 Borcuk 52/155 OTHER PUBLICATIONS The Anchoring Handbook," Northhill Co., Inc., Los Angeles, Calif., copyright 1943, page 2.

Primary Examiner-Price C. Faw, Jr. Attorney, Agent, or Firm-Cameron, Kerkam, Sutton, Stowell & Stowell ABSTRACT A ground anchor which is self-righting and selfengaging under the action of the anchor rope, comprises a shank with an oblique fluke plate at one end and a self-righting device at the other. The selfrighting device has a plurality of arms fixed to and projecting laterally from the shank, arranged such that by pulling on the anchor rope when the anchor is disorientated at least one of the arms engages the ground and reacts with the ground to correct the orientation of the anchor for correct ground engagement of the fluke plate. The self-righting device can include three arms, one arm being perpendicular to the other two arms which are in line, on either side of the shank.

9 Claims, 4 Drawing Figures PAIENTED mm 3,828, 19 7 sum 1 or 4 PATENTEflAumaxm 9 3 8:28 497 SHEET u 0F 4 FIG. 4

GROUND ANCHORS This invention relates to a ground anchor which can be propelled from a land, sea or amphibious vehicle and which is self-righting and self-engaging under the action of the anchor rope, and more particularly relates to the self-righting and self-engaging anchor which may be rocket propelled from an amphibious armoured vehicle.

Hand-placed anchors have been suggested for use with amphibious armoured vehicles, but the operation of emplacing the anchor is time consuming and in a hostile military environment emplacement may be particularly difficult and may involve exposure of personnel which may not always be acceptable. The invention provides an anchor which is suitable for rocket propulsion from an amphibious armoured vehicle and which, on application of tension through the rope of the anchor, will right itself for correct engagement with the ground. Subsequent tension on the anchor will cause the anchor to engage the ground to develop a holding resistance.

For example an amphibious armoured vehicle, which is about to negotiate the exit bank of a water obstacle can launch the anchor onto the land and by operating the vehicle winch to pull on the anchor rope will cause the anchor to orientate itself for correct ground engagement and to engage the ground until sufficient holding resistance is achieved, whereafter the armoured vehicle can winch itself clear of the obstacle.

Broadly the invention provides a ground anchor which is self-righting and self-engaging under the action of the anchor rope, and which comprises an elongated shank; a fluke plate oblique to the shank and rigidly attached to one end of the shank for ground engagement of the anchor; and a self-righting device attached to the said shank for correcting the orientation of the anchor to effect correct ground engagement of the fluke plate of the anchor, the said self-righting device comprising a plurality of arms fixed to and projecting laterally from the shank at a point or points on the shank spaced longitudinally from the fluke plate and so arranged that on application of tension through the rope of the anchor when the anchor is disorientated, at least one of the said plurality of arms engages the ground and reacts with the ground to reorientate the anchor for correct ground engagement of the fluke plate.

Preferably the self-righting device comprises three arms each fixed to and spaced around the shank, near to the end remote from the fluke plate;

One of the said three arms may conveniently be mounted on the shank at an acute angle to the direction of the shank away from the fluke plate.

According to one feature of the invention the said one of the said three arms is mounted perpendicular to the other two arms which are in line and extend either side of the shank perpendicular thereto and parallel to the plane of the fluke plate.

According to another feature of the invention the shank is formed from a flat strip and the fluke plate, having at least two pointed prongs, is rigidly fixed to the shank member in a plane perpendicular to the plane of the shank. The said one of the said three arms may be fixed to and may project from the shank in the plane of the shank, and the said other two arms may be mounted in a plane perpendicular to the plane of the shank.

Preferably the fluke plate projects on one side of the shank and the said one of the said three arms is arranged to project from the shank on the opposite side thereof.

Preferably the said plurality of arms are provided with sharpened ends to facilitate ground engagement. The sharpened ends may comprise flat spade members attached to the ends of the arms, either with or without single or double prongs.

The anchor may also be fitted with a rocket motor, so that the anchor can be propelled to a suitable location where the ground conditions allow easy engagement of the anchor and adequate holding resistance. The rocket motor is preferably mounted on and parallel to the shank, and the anchor is propelled flukeplate-first.

An example of one particular arrangement of the invention will now be described with reference to the drawings in which,

FIG. 1 is a side view of a self-engaging self-righting anchor;

FIG. 2 is a view in the direction of arrow II in FIG.

FIG. 3 is a view in the direction of arrow III in FIG.

FIG. 4, is a perspective view of the anchor.

The drawings illustrate a self-righting and selfengaging ground anchor fitted with a rocket motor to enable the anchor to be propelled from a land or amphibious vehicle. Such an anchor, capable of developing a holding resistance in light sandy soils of up to 5 tons, has been designed for use on amphibious armoured vehicles equipped with forward acting winches when negotiating the exit banks of water obstacles.

Referring to the figures the anchor includes a flat elongated shank plate 1 which tapers along its length and which consists of a shank body 2 with a curved portion 3a and an extension 3b at the larger end of the shank l. The curved portion 3a and extension 3b are hereinafter referred to as the throat 3 of the anchor. A shackle 16 is attached to the narrow end of the shank body 2 and is arranged to be attached to the anchor rope (not shown). A composite fluke plate 4 comprises a pair of similar plates 7, 8 which are fixed together by bolts 34 through lugs 42 and 43 on the plates 7 and 8 respectively. The plates 7, 8 are located one on either side of the throat 3 and have web parts 9, 10 along the edges adjacent to throat 3 (FIG. 2). The web parts Q, 10 of the plates 7, 8 are clamped together on to distance pieces by bolts 35 and 36 and are held to the throat 3 of the anchor by quick acting pins 5 and 6. The plates 7, 8 which have strengthening fins 29, 30, extend laterally on either side of the throat 3 so that the composite fluke plate 4 lies in a plane perpendicular to the plane of the shank plate 1. The fluke plate 4 has two prongs ll, 12, which are the respective tapered portions of the plates 7 and 8. The extremities of the prongs 1 l, 12 are fitted with spade members 23, 24, respectively, to facilitate ground engagement.

The self-righting device consists of three arms l3, l4 and 15 projecting laterally from the body 2 of the shank plate 1 near to the shackle 16. The arm 15 comprises two parallel equal lengths of angle bracket 17 and 18 which are bolted together at one end one on either side of the shank body 2 at 31, 32. The arm 15 is mounted on the shank plate 1 at an acute angle to the forward or narrow end of the anchor near to the shackle 16. The lengths of angle bracket 17, 18 are chamfered at their free ends, which are also connected by a thin plate 19 which extends slightly beyond the ends of the lengths of angle bracket 17, 18 to provide a sharpened spade member. The arms 13 and 14 comprise a single length of angle bracket 20 which is mounted on the shank body 2 and is bolted (not shown) to both of the lengths of angle bracket 17, 18 of the arm 15. The angle bracket 20 extends symmetrically on each side of the shank body 2 perpendicular to the plane of the shank plate 1. Alternatively the arms 13 and 14 may be mounted on the shank plate 1 at an acute angle to the forward or narrow end of the anchor. Pointed spade members 21, 22 are fitted to the free ends of the arms 13 and 14 respectively.

A lug 33 is clamped between and extends rearward of the angle brackets 17 and 18 on the shank body 2. The lug 33 has a hole 37 to take a hook on one end of a short length of steel wire rope (not shown). A hole 38 is drilled in the throat 3 to take a shackle for the other end of the steel wire rope. The anchor can be removed from the ground by disengaging the hook at one end of the steel wire from the hole 37, attaching it to the vehicle tow or winch rope and pulling in the rearward direction of the anchor.

The anchor is fitted with a rocket motor 25 which is mounted substantially parallel to the lower edge 40 of the shank body 2 by a lug 27 fixed to the shank body 2. The lug 27 has a quick release attachment 28 comprising a bracket held to the lug 27 by a split pin and a clip which surrounds and supports the rocket motor. The opposite end of the rocket motor 25 from the nozzle has a nose plug with a Vee end which engages a notch in the thin plate 39 which is bolted to the anchor at the rear end of the shank body 2 and in front of the throat 3 of the anchor. The quick release attachment will withstand the forces of launching, but the high inertia forces of between l-200 times gravity experienced when the anchor lands are sufficient to fracture the clip or the bracket, depending on the orientation of the anchor as it strikes the ground. In this way the expended rocket motor 25 becomes detached from the anchor on landing, and will not obstruct the engagement of the anchor in the ground.

The size of the lug 27 and attachment 28 are arranged such that the rocket motor 25 passes through or close to the centre of gravity (CG) of the anchor, which is located between the edge 40 of the shank body 2 and the fluke plate 4 in front of the plate 39 and throat 3 of the anchor.

When ready for take-off the anchor is mounted fluke plate first on a launching pad on the amphibious vehicle. The launching pad supports the anchor at the shackle l6 and at the ends of the prongs l1, 12 of the fluke plate 4, such that the rocket motor 25 and the edge 40 of the shank body 2 make an angle of about 40 with the horizontal. The anchor rope comprises a short steel wire rope strop from the shackle 16 of the anchor, a short plaited polypropylene strop (to provide a shock absorber and to take up any twist in the winch rope), and the vehicle winch rope, all shackled together. It has been found convenient to prepare the anchor rope prior to launching for rapid dispensing. A crab-pot dispenser, consisting of an odd number of steel prongs arranged around the circumference of a circle with their free ends turned slightly inward, has proved successful in use. The crab-pot dispenser is placed near to the fluke plate of the anchor, pointing in the direction of launching.

When the anchor has been launched it may land and rest in any one of several orientations. It is possible that the anchor may land in the correct position for ground engagement with only the shackle l6 and the prongs 11 and 12 of the fluke plate 4 making contact with the ground. in this position none of the arms 13, 14 or 15 of the self-righting device makes contact with the ground and the anchor is not disorientated. The anchor, in this position, will engage itself in the ground under the pulling action of the winch on the anchor rope, which will generally be in a horizontal direction, and will cause the prongs l1 and 12 of the fluke plate 4 to penetrate the ground. The penetration will continue under the pulling action until sufficient resistance is provided by the anchor, or until the maximum resistanceis reached. Maximum resistance occurs when the moment caused by the reaction of the ground to the force of the anchor is equal to the moment caused by the pull on the anchor, and occurs when substantially the whole length of the shank body 2 and throat 3 have penetrated the ground.

lt is more likely that the launched anchor will land and rest at some other orientation than with ground contact at the prongs l1 and 12 and shackle 16. The anchor may land in the fully upturned position with the fluke plate 4 clear of the ground, and the anchor making ground contact at the throat 3, the free end of the arm 15 and at the free end of either of the arms 13 and 14. Such an orientation of a deployed anchor with the free end of the arm 14 in contact with the ground is illustrated in FIG. 4. Forward pulling action on the anchor rope from the direction of the shackle 16 forces the free end of the arm 15 into the ground, and may also force the free end of arm 14 into the ground, until th throat 3 of the anchor lifts off the ground. Further pulling on the anchor rope causes the unstable anchor to tilt over towards the arm 14. The tilting continues, forcing the arm 14 into or further into the ground until the anchor falls on its side, with the shank plate 1 parallel to the ground and the arm 14 reacting with the ground, the arm 15 having been pulled clear of the ground as the anchor topples over. In this position the anchor makes contact with the ground at the arm 14 and along the edge of one side of the fluke plate 4. Still further pulling on the anchor rope will cause the prong 12, in contact with the ground, to engage and penetrate the ground, and the reaction of the ground at this point and at the point of ground engagement of the arm 14 will right the anchor into the position for correct ground engagement, which has been described previously.

Other orientations at which a launched anchor may land and rest are corrected by a similar pulling action on the anchor rope. For example the anchor may land on its side making contact with the ground at one of the arms 13 or 14 and along the edge of one of the sides of the fluke plate 4, which is the intermediate position when a fully'upturned anchor is being righted.

The exact manner of righting the anchor will vary depending on the type of ground on which the anchor lands and on the type of soil that is engaged. For example the tilting and lifting action described which causes the fully upturned anchor to fall onto its side, may for different ground conditions become a somersaulting, slewing or even rolling over action. Furthermore the manner of the righting action depends on the physical characteristics of the type of anchor, such as the position of the three arms 13, 14 and of the self-righting device relative to the shackle 16, the centre of gravity (CG) of the anchor and the shape of the fluke plate 4 and shank plate 1.

Although the several stages of righting and engaging the upturned anchor have been conveniently described in relation to separate pulling actions, in practice the righting and engaging of the anchor occurs as a continuous process under the steady pull of the winch on the anchor rope.

In the particular arrangement of the anchor described with reference to the drawings a two pronged fluke plate 4 is used rather than a conventional single fluke plate, as it helps to ensure stable ground engagement of the anchor and helps to eliminate any tendency, particularly during self-righting, to fall over sideways or rotate around the line of pull.

When engaging the anchor in turf-like or dense vegetation it is necessary to ensure that the fluke'plate'is well buried and therefore able to exert sufficient engagement force to pull the shank plate 1 into the ground. It has been found that increasing the length of the throat 3 to offset the shank further from the fluke plate 4, and fitting a thin plate 39 in front of the throat 3 and at the rear end of the shank body 2 to form a cutting edge, helps to ensure that the anchor is well buried under the action of the anchor rope and avoids any tendency of the dense matted vegetation such as coarse grass to choke-up the space between the fluke plate 4 and the shank plate 1.

The anchor described has a shank/fluke plate angle (i.e., the angle between the fluke plate 4 and the line joining the shackle 16 to the rearrnost point 41 of the fluke plate)4 of approximately 28". It has been shown that the particular form of self-righting and selfengaging anchor will operate satisfactorily with shank/- fluke angles in the range 35, but the maximum ground resistance is obtained when the shank/fluke angle lies in the range 25-30. Smaller angles do not achieve the full potential resistance of the anchor whilst larger angles result in loss of resistance through instability as the resultant of the tension in the anchor rope and the resisting forces tend to lift the anchor out of the ground. A shank/fluke plate angle in the range 2530 results in a maximum inclination of the fluke plate to the horizontal of between 8 and l5 when the anchor is fully engaged developing maximum resistance.

Experiments with the anchor described have shown that in general the optimum inclination of the fluke plate 4 to the ground at the beginning of engagement lies in the range 4550. Angles in this range offer good self-engaging and ground penetration properties combined with good ground resistance properties when fully engaged.

An anchor of the kind described having a shank/fluke angle in the range 2530 and an engagement angle within the range 4550 will have a ratio of shank length to fluke length of between 1.8 and 2.7 approximately. The shank length is defined as the distance between the shackle and the rear-most point 41 of the fluke plate 4, and the fluke length is defined as the maximum overall length of the plate, making no allowance The ground resistance of the self-engaging and self righting anchor depends on the overall size of the anchor, the larger the area of the fluke plate the greater the ground resistance. Furthermore it has been found that the total ground resistance is approximately a linear function of the ratio of shank length to fluke length. However the geometry of the anchors which form the subject of this invention is dictated almost entirely by the requirements for self-engagement, self-righting, and stability under load.

The arm 15 of the self-righting device is mounted on the shank body 2 at an angle of approximately 41 to the narrow, tapered end of the tapered shank plate 1. At this angle, when the anchor rests on the ground in the fully upturned position with the fluke plate clear of the ground and the throat making contact with the ground, the arm 15 will engage the ground at an angle of about.35 at the beginning of engagement. It has been found that the best self-righting properties of the anchor are experienced when the arms 13 and 14 are of equal length and are symmetrically located either side of the shank body 2, the combined length of the arms13 and 14, including the spade members 21 and 22 exceeding the width of the fluke plate 4 by about 60 percent. Furthermore the length of the arm 15 from the centre line of the shank, is approximately the same as the length of the arm 13 or 14.

The self-righting device is positioned on the shank body 2 near to the narrow tapered end of the shank, and in the example of the invention described the distance between the centre of the shackle 16, and the bolt 32 is slightly less then the length of the arm 13 or 14.

The self-righting and self-engaging anchor described is of considerable benefit to certain military armoured vehicles as it increases their capacity to negotiate water obstacles. Previously such vehicles were often unable to negotiate water obstacles, which had steep, soft or boggy exit or entry slopes, fast flowing currents or hidden underwater obstructions such as steps.

Although particularly designed for rocket launching from amphibious armoured vehicles the anchor may, should the need arise, be hand placed. The self-righting device and self-engaging design of the anchor would still confer the advantage that the exposure time of personnel deploying the anchor in a hostile military environment would be kept down to acceptable proportions since time need not be wasted in correctly orientating the anchor. The anchor may also be used by an amphibious vehicle as a ground anchorage prior to the entry of the vehicle into a water obstacle. For example the anchor rope could be used as a safety line for a vehicle investigating the feasibility of a river crossing, particularly under the adverse conditions experienced when attempting to cross exceptionally strong flowing rivers.

The anchor is not limited to use with land or amphibious vehicles, and may be used by vessels such as barges requiring an anchorage on land or in shallow water.

I claim:

l. A ground anchor to which an anchor rope can be attached and which is self-rightable and selfengageable under the action of the anchor rope and which can be propelled from a vehicle, comprising,

a. an elongated shank,

b. a single fluke plate oblique to the shank and rigidly attached to one end of and on one side of the shank, for ground engagement of the anchor, and

c. a self-righting device attached to the said shank for correcting the orientation of the anchor to effect correct ground engagement of the said fluke plate of the anchor, the self-righting device comprising three laterally projecting ground engageable arms each fixed to and spaced around the said shank near the end thereof remote from the said fluke plate, one of said laterally projecting ground engageable arms being mounted substantially perpendicularly to the other two arms and projecting from the shank on the opposite side thereof from the said single fluke plate, the said other two arms being substantially in line and extending on either side of the shank substantially perpendicular thereto and substantially parallel to the said fluke plate, so that on application of tension through the anchor rope of the anchor when disorientated at least one of the said three arms engages the ground to reorientate the anchor for correct ground engagement of the said fluke plate.

2. A ground anchor as climed in claim 1 wherein the said one of the said arms being mounted substantially perpendicular to the other two arms, is fixed to the said shank at an acute angle to the direction of the shank away from the said fluke plate.

3. A ground anchor as claimed in claim 1 wherein the said shank is formed of a substantially flat strip and the said fluke plate has at least two prongs, and is rigidly fixed to the shank in a plane perpendicular to the plane of the shank.

4. A ground anchor as claimed in claim 1 wherein the said shank is formed of a substantially flat strip and the said one of the said three arms being mounted substantially perpendicular to the other two arms is fixed to and projects from the said shank in the plane of the shank, and the said other two arms are mounted in a plane perpendicular to the plane of the said shank.

5. A ground anchor as claimed in claim 1 wherein each of the said plurality of arms has a sharpened end thereon to facilitate ground engagement.

6. A ground anchor as claimed in claim 5 wherein each of the said sharpened ends comprises a flat spade member, such spade member being attached to the end of each of the said plurality of arms.

7. A ground anchor as claimed in claim 1 having a rocket motor attached thereto adapted so that the anchor can be propelled to a suitable location for ground engagement.

8. A ground anchor as claimed in claim 7 wherein the said rocket motor is elongated and is mounted on and parallel to the said shank.

9. A ground anchor as claimed in claim 8 wherein the said rocket motor is mounted in line with the centre of gravity of the anchor, and is arranged so that the anchor can be propelled fluke plate first. 

1. A ground anchor to which an anchor rope can be attached and which is self-rightable and self-engageable under the action of the anchor rope and which can be propelled from a vehicle, comprising, a. an elongated shank, b. a single fluke plate oblique to the shank and rigidly attached to one end of and on one side of the shank, for ground engagement of the anchor, and c. a self-righting device attached to the said shank for correcting the orientation of the anchor to effect correct ground engagement of the said fluke plate of the anchor, the self-righting device comprising three laterally projecting ground engageable arms each fixed to and spaced around the said shank near the end thereof remote from the said fluke plate, one of said laterally projecting ground engageable arms being mounted substantially perpendicularly to the other two arms and projecting from the shank on the opposite side thereof from the said single fluke plate, the said other two arms being substantially in line and extending on either side of the shank substantially perpendicular thereto and substantially parallel to the said fluke plate, so that on application of tension through the anchor rope of the anchor when disorientated at least one of the said three arms engages the ground to reorientate the anchor for correct ground engagement of the said fluke plate.
 2. A ground anchor as climed in claim 1 wherein the said one of the said arms being mounted substantially perpendicular to the other two arms, is fixed to the said shank at an acute angle to the direction of the shank away from the said fluke plate.
 3. A ground anchor as claimed in claim 1 wherein the said shank is formed of a substantially flat strip and the said fluke plate has at least two prongs, and is rigidly fixed to the shank in a plane perpendicular to the plane of the shank.
 4. A ground anchor as claimed in claim 1 wherein the said shank is formed of a substantially flAt strip and the said one of the said three arms being mounted substantially perpendicular to the other two arms is fixed to and projects from the said shank in the plane of the shank, and the said other two arms are mounted in a plane perpendicular to the plane of the said shank.
 5. A ground anchor as claimed in claim 1 wherein each of the said plurality of arms has a sharpened end thereon to facilitate ground engagement.
 6. A ground anchor as claimed in claim 5 wherein each of the said sharpened ends comprises a flat spade member, such spade member being attached to the end of each of the said plurality of arms.
 7. A ground anchor as claimed in claim 1 having a rocket motor attached thereto adapted so that the anchor can be propelled to a suitable location for ground engagement.
 8. A ground anchor as claimed in claim 7 wherein the said rocket motor is elongated and is mounted on and parallel to the said shank.
 9. A ground anchor as claimed in claim 8 wherein the said rocket motor is mounted in line with the centre of gravity of the anchor, and is arranged so that the anchor can be propelled fluke plate first. 